Self-Assembly and Chaining of Particles in Viscoelastic Liquids: Fundamentals and Applications

CBET-0828104范围远程优点：拟议的工作寻求我们的理解，并建立聚合物溶液(粘弹性流体)流动中小颗粒的聚集、自组装和链接特性的应用。粘弹性流体中的颗粒-颗粒相互作用与牛顿流体中的颗粒相互作用有很大的不同：颗粒在牛顿流体流动中分散，在粘弹性流体流动中聚集。我们所做的分析表明，粘弹性液体中颗粒的链结是局部的，并基于两个支柱：第一个支柱是粘弹性压力？由剪切产生的法向应力产生。第二个原因是由于我们在二阶流体中计算的法向应力符号的变化。为了验证这一理论，将进行不同的数值实验和实验。我们将建立颗粒在粘弹性流体中聚集的颗粒尺寸、浓度、颗粒与流体密度比、液体流变参数、流场等的限制。粒子图像测速技术(PIV)的基本假设是，在流体中播撒的小颗粒在流动中不会发生相互作用。这一假设对于示踪剂颗粒分散的牛顿流体是有效的，但在颗粒聚集的情况下不适用于粘弹性流体。这项研究将确定小颗粒跟踪流动的条件，就像PIV研究中假设的那样。了解粒子相互作用和链接发生的参数的范围将有助于石油、复合材料、食品和制药行业的其他几个应用。广泛的影响：通过加州大学欧文分校现有的项目协调新研究生的招生，将鼓励妇女和代表不足群体的个人参与拟议的努力。这些面向学生的方案旨在鼓励妇女和少数族裔参与科学和工程领域，其中包括工程机会和多样性中心(CODE)和加州国家科学基金会路易斯·斯托克斯少数族裔参与联盟(CAMP)。其中一名COPIS是UCI CAMP部门主任，他将在该项目与校园中对研究感兴趣的代表不足的STEM学生之间建立联系。研究团队包括两名女研究生。2005年，在加州大学亨利·萨缪利工程学院招收的630名研究生中，女性研究生占150人，占学生总数的24%。这一努力产生的研究生水平的研究机会将用于支持这些在工程学方面代表性不足的研究生，并为提升到博士后水平和未来在学术界取得成就奠定坚实的基础。该项目还将通过UCI的本科生研究机会计划(UROP)为本科生提供研究机会。调查人员参与这个项目有很长的历史，并将确保本科生的参与，特别是在项目的实验方面。

CBET-0828104RangelIntelectual Merit: The proposed work seeks our understanding and establishes applications of the properties of aggregation, self-assembly and chaining of small particles in flows of polymer solutions (viscoelastic fluids). Particle-particle interactions in viscoelastic fluids are dramatically different than in Newtonian fluids: particles disperse in the flow of Newtonian fluids and they aggregate in the flow of viscolastic fluids. We have done analyses which suggest that the chaining of the particles in viscoelastic liquids is local and based on two pillars; the first is a viscoelastic ?pressure? generated by normal stresses due to shear. The second is due to the change in the sign of the normal stress which we compute in the second-order order fluid. Different numerical and experimental experiments will be carried out to validate this theory. We will establish the limits of particle size, concentration, particle to fluid density ratio, liquid rheological parameters, flow field etc for which particles aggregate in viscoelastic fluids. The basic assumption of particle image velocimetry (PIV) is that small particles seeded in fluid will not interact in flow. This assumption is valid for Newtonian fluids where tracer particles disperse, but it will not work in viscoelastic fluids in situations in which particles aggregate. This study will determine the conditions under which small particles track the flow, as is assumed in studies of PIV. Understanding the rage of parameters at which interaction and chaining of particles occurs will benefit several other applications in oil, composite, food, and pharmaceutical industries.Broader Impacts: The participation of women and individuals of underrepresented groups in the proposed effort will be encouraged by coordinating recruitment of new graduate students through established programs at UC Irvine. These student oriented programs are designed to encourage the participation of women and minorities in the science and engineering fields and include the Center for Opportunities and Diversity in Engineering (CODE) and the California NSF Louis Stokes Alliance for Minority Participation (CAMP). One of the coPIs is the UCI Division Director for CAMP and he will provide a connection between this project and the underrepresented STEM students on campus interested in research. The research team includes two female graduate students. In 2005, female graduate students comprised 150 out of a total number of 630 graduate students enrolled in the Henry Samueli School of Engineering at UCI, representing 24% of the student body. The graduate level research opportunities generated by this effort will be used to support these underrepresented graduate students in engineering and provide a solid base for advancement to the postdoctoral level and future achievement in academia. The project will also provide research opportunities for undergraduate students through the Undergraduate Research Opportunities Program (UROP) at UCI. The investigators have a long history of involvement in this program and will ensure the participation of undergraduates, particularly in the experimental aspects of the project.